It is known from the prior art of DE-A-19645678 or DE-A-19811372, to provide an operating panel for an electrical appliance or domestic appliance under which at a specific application forming a so-called operating field is provided a pressure-sensitive piezoelectric element. If a pressure is exerted on the cover, which can be made from thin high-grade steel or aluminium for example, said pressing action through the piezoelectric element can be evaluated as a desired operation. An associated evaluation or control gives a signal to the electrical appliance. It is considered disadvantageous that the use of piezoelectric elements give rise to certain disadvantages, particularly because they are in part mechanically fault-prone and cannot be easily installed in an appliance. It is also frequently necessary to use special manufactures or components for piezoelectric elements, which negatively influences expenditure, particularly costs and short-term availability. The use of other sensor elements, such as capacitive or optical sensor elements, suffers from the disadvantage that they can only be used behind metallic operating panels at present at a high cost or not at all or an optical transparency is vital for an optical system.